Arcadia, although I didn't ever think I'd die during labour, nor did I had fears of dying leading up to the birth, I did however feel the same way you described, in those last pushing stages where DD got stuck (she was posterior) and I had been pushing almost 2hrs total, and tore really badly and felt every single part of that tearing and crowning as I had no drugs (or gas) whatsoever..... that pain I will NEVER forget. It was horrific pain. I honestly thought if it went on any longer I would not be able to cope.... hence why I started swearing during that part.... (what a lady ) but I had every reason to!!!! LOL
In saying this, I too, can't imagine birthing with drugs, I would never change a thing..... I loved having a natural birth and look forward to the next one being natural also. If you ask me, its the only way to do it!!

Like Catherine said, you work with it and let your body guide you..... any fears that enter your mind you quickly brush them away with positive thoughts that bub will be here soon...... eventually they all have to come out!!